Impact of New Accounting Standards and Interpretations	6 Months Ended
Mar. 31, 2016
Accounting Changes and Error Corrections [Abstract]
Impact of New Accounting Standards and Interpretations	Impact of New Accounting Standards and Interpretations The following accounting standard was adopted by TVA on October 1, 2015. Debt Issuance Costs. In April 2015, the Financial Accounting Standards Board ("FASB") issued guidance that changes the presentation of debt issuance costs in financial statements. This standard requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct reduction of that debt liability, consistent with debt discounts, including retrospectively adjusting all prior periods presented. TVA early adopted the standard on October 1, 2015. In the consolidated balance sheets, TVA reclassified $80 million of debt issuance costs previously presented in Other long-term assets on the September 30, 2015 Consolidated Balance Sheets and presented these amounts as a reduction to Long-term power bonds, net and Long-term debt, net of variable interest entities. The guidance does not change the recognition and measurement of debt issuance costs. The following accounting standards have been issued, but as of March 31, 2016, were not effective and had not been adopted by TVA. Revenue Recognition. In May 2014, the FASB issued a new revenue recognition standard that applies to revenue from contracts with customers. The standard requires that an entity recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In August 2015, the FASB issued a one-year deferral of the effective date. The standard becomes effective for TVA on October 1, 2018, and allows for either a full retrospective or a modified retrospective application. Early adoption of the standard is permitted for TVA on October 1, 2017. TVA is currently evaluating the potential impact of these changes on its consolidated financial statements and related disclosures and the application method to be used. Consolidation. In February 2015, the FASB issued guidance that amends the consolidation analysis for VIEs as well as voting interest entities. The standard reduces the number of consolidation models through the elimination of the indefinite deferral for certain entities that was previously allowed and places more emphasis on risk of loss when determining a controlling financial interest. The standard becomes effective for TVA on October 1, 2016, and allows for either a full retrospective or a modified retrospective application. TVA has evaluated the impact of adopting this guidance and expects no material impact on TVA's financial condition, results of operations, or cash flows. Inventory Valuation. In July 2015, the FASB issued guidance that changes the model used for the subsequent measurement of inventory from the previous lower of cost or market model, to the lower of cost or net realizable value. The guidance applies only to inventory valued using methods other than last-in, first out or the retail inventory method (for example, first-in, first-out or average cost). This amendment is intended to simplify the subsequent measurement of inventory. The standard becomes effective for TVA on October 1, 2017, including interim periods within the fiscal year that begins on that date, and is required to be applied prospectively. Early adoption is permitted. TVA is currently evaluating the potential impact of these changes on its consolidated financial statements. Lease Accounting. In February 2016, the FASB issued a new lease standard that changes the provisions of recognition in both the lessee and lessor accounting models. The standard requires entities that lease assets – referred to as “lessees” – to recognize on the balance sheet the assets and liabilities for the rights and obligations created by leases with terms of more than 12 months. The recognition, measurement, and presentation of expenses and cash flows arising from a lease by a lessee primarily will depend on its classification as a finance (similar to current capital leases) or operating lease. However, unlike current lease accounting rules – which require only capital leases to be recognized on the balance sheet – the new standard will require both types of leases to be recognized on the balance sheet. Operating leases will result in straight-line expense, while finance leases will result in recognition of interest on the lease liability separately from amortization expense. The accounting for the owner of the assets leased by the lessee – also known as lessor accounting – will remain largely unchanged from current lease accounting rules. The standard becomes effective for TVA on October 1, 2019, including interim periods within that fiscal year, and is required to be applied using a modified retrospective transition. Early adoption is permitted. TVA is currently evaluating the potential impact of these changes on its consolidated financial statements and related disclosures.

Impact of New Accounting Standards and Interpretations

The following accounting standard was adopted by TVA on October 1, 2015.

Debt Issuance Costs. In April 2015, the Financial Accounting Standards Board ("FASB") issued guidance that changes the presentation of debt issuance costs in financial statements. This standard requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct reduction of that debt liability, consistent with debt discounts, including retrospectively adjusting all prior periods presented. TVA early adopted the standard on October 1, 2015. In the consolidated balance sheets, TVA reclassified $80 million of debt issuance costs previously presented in Other long-term assets on the September 30, 2015 Consolidated Balance Sheets and presented these amounts as a reduction to Long-term power bonds, net and Long-term debt, net of variable interest entities. The guidance does not change the recognition and measurement of debt issuance costs.

The following accounting standards have been issued, but as of March 31, 2016, were not effective and had not been adopted by TVA.

Revenue Recognition. In May 2014, the FASB issued a new revenue recognition standard that applies to revenue from contracts with customers. The standard requires that an entity recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In August 2015, the FASB issued a one-year deferral of the effective date. The standard becomes effective for TVA on October 1, 2018, and allows for either a full retrospective or a modified retrospective application. Early adoption of the standard is permitted for TVA on October 1, 2017. TVA is currently evaluating the potential impact of these changes on its consolidated financial statements and related disclosures and the application method to be used.

Consolidation. In February 2015, the FASB issued guidance that amends the consolidation analysis for VIEs as well as voting interest entities. The standard reduces the number of consolidation models through the elimination of the indefinite deferral for certain entities that was previously allowed and places more emphasis on risk of loss when determining a controlling financial interest. The standard becomes effective for TVA on October 1, 2016, and allows for either a full retrospective or a modified retrospective application. TVA has evaluated the impact of adopting this guidance and expects no material impact on TVA's financial condition, results of operations, or cash flows.

Inventory Valuation. In July 2015, the FASB issued guidance that changes the model used for the subsequent measurement of inventory from the previous lower of cost or market model, to the lower of cost or net realizable value. The guidance applies only to inventory valued using methods other than last-in, first out or the retail inventory method (for example, first-in, first-out or average cost). This amendment is intended to simplify the subsequent measurement of inventory. The standard becomes effective for TVA on October 1, 2017, including interim periods within the fiscal year that begins on that date, and is required to be applied prospectively. Early adoption is permitted. TVA is currently evaluating the potential impact of these changes on its consolidated financial statements.

Lease Accounting. In February 2016, the FASB issued a new lease standard that changes the provisions of recognition in both the lessee and lessor accounting models. The standard requires entities that lease assets – referred to as “lessees” – to recognize on the balance sheet the assets and liabilities for the rights and obligations created by leases with terms of more than 12 months. The recognition, measurement, and presentation of expenses and cash flows arising from a lease by a lessee primarily will depend on its classification as a finance (similar to current capital leases) or operating lease. However, unlike current lease accounting rules – which require only capital leases to be recognized on the balance sheet – the new standard will require both types of leases to be recognized on the balance sheet. Operating leases will result in straight-line expense, while finance leases will result in recognition of interest on the lease liability separately from amortization expense. The accounting for the owner of the assets leased by the lessee – also known as lessor accounting – will remain largely unchanged from current lease accounting rules. The standard becomes effective for TVA on October 1, 2019, including interim periods within that fiscal year, and is required to be applied using a modified retrospective transition. Early adoption is permitted. TVA is currently evaluating the potential impact of these changes on its consolidated financial statements and related disclosures.